Western Caribbean disturbance 96L growing more organized

A region of disturbed weather in the Western Caribbean (Invest 96L) is bringing heavy rains to coastal Nicaragua, and has the potential to develop into a tropical depression this weekend. Visible satellite loops show that 96L is beginning to show signs of organization. Some rotation is apparent, and the upper-level cirrus clouds streaming away from the center indicate that 96L is establishing an upper-level outflow channel to the east. The heavy thunderstorm activity is quite limited at present, because a large region of dry air to the east of 96L is interfering with development, as seen on water vapor satellite loops. An ASCAT pass at 11:05 am EDT showed no signs of a surface circulation, with surface winds in the 25 - 30 mph range. Surface pressures are slowly falling at San Andres Island, near the center of 96L. Wind shear is a moderate 10 - 20 knots in the region, and is expected remain in the moderate range through Monday. Water temperatures are very warm, 29 - 30°C, and these warm waters extend to great depth.

Figure 1. Afternoon satellite image of 96L.

Forecast for 96LThe moderate wind shear and warm waters should allow some modest development of 96L over the next few days, though this will be slowed by the dry air to the storm's east. The models are quite enthusiastic about developing 96L into a tropical depression, and our top four reliable models for forecasting genesis--the ECMWF, GFS, UKMET, and NOGAPS--have all been predicting formation of a tropical depression by Monday in one or more of their runs over the past day. 96L is in an area of weak steering currents, and will move little over the next three days. On Tuesday and Wednesday, a strong trough of low pressure will be passing over the Eastern U.S., and this trough has the potential to turn 96L northwards into Cuba. This is more likely to happen if 96L is stronger and deeper, and thus able to "feel" the upper-level winds the trough will bring. The 12Z run of the GFS model and 00Z runs of the ECMWF and UKMET models predict 96L will develop into a tropical storm that hits Western Cuba on Wednesday or Thursday, and potentially affecting the Cayman Islands, South Florida, and the Bahamas as well. If 96L remains a weak and shallow system, it is more likely to stay trapped in the Western Caribbean and make landfall in Nicaragua. This is the solution of the NOGAPS model, which has 96L moving ashore on Tuesday over Nicaragua as a weak system. NHC gave 96L a 30% chance of developing into a tropical depression by Sunday in their 8 am Tropical Weather Outlook. A hurricane hunter mission is scheduled to investigate 96L Saturday afternoon.

I'll have a new post on Saturday, but might wait until the afternoon, when the hurricane hunter data becomes available.

LONG TERM (TUESDAY THROUGH FRIDAY)...CONSIDERABLE UNCERTAINTY CLOUDS THE LONG-TERM PORTION OF THISFORECAST...AS MODEL INCONSISTENCY REGARDING THE DEVELOPING LOWPRESSURE CENTER CURRENTLY OVER THE SOUTHWESTERN CARIBBEAN SEAPERSISTS. THERE APPEARS TO BE LITTLE IN THE WAY OF STEERING FLOW OVERTHE WESTERN CARIBBEAN DURING THE EARLY AND MIDDLE PORTIONS OF THEUPCOMING WEEK...AND THE PROXIMITY OF THE ORGANIZING LOW PRESSURECENTER TO THE CENTRAL AMERICAN COAST WILL LIKELY DICTATE HOW MUCHDEVELOPMENT OCCURS. A PROGRESSIVE TROUGH TRAVERSING THE WESTERN ANDCENTRAL UNITED STATES MAY SHARPEN ENOUGH TO PULL THIS SYSTEMNORTHWARD BY LATE NEXT WEEK. HOWEVER...THE ECMWF HAS FLIP-FLOPPEDFROM ITS PRIOR SOLUTION ON ITS 00Z RUN AND NO LONGER SHOWS A TROPICALCYCLONE EMERGING INTO THE SOUTHEASTERN GULF OF MEXICO.

CLOUDINESS AND THUNDERSTORMS ASSOCIATED WITH A NEARLY STATIONARYAREA OF LOW PRESSURE IN THE SOUTHWESTERN CARIBBEAN SEA NEAR SANANDRES ISLAND HAVE NOT BECOME ANY BETTER ORGANIZED SINCE YESTERDAY.ALTHOUGH SURFACE PRESSURES HAVE CONTINUED TO FALL IN THEAREA...ENVIRONMENTAL CONDITIONS APPEAR TO BE A LITTLE BIT LESSFAVORABLE FOR A TROPICAL DEPRESSION TO FORM DURING THE NEXT DAY ORTWO. HOWEVER...THIS SYSTEM STILL HAS A HIGH CHANCE...60 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS.

A BROAD AREA OF LOW PRESSURE LOCATED SEVERAL HUNDRED MILES EAST OFTHE SOUTHERN WINDWARD ISLANDS IS PRODUCING DISORGANIZED CLOUDINESSAND THUNDERSTORMS. THIS ACTIVITY HAS BEEN GRADUALLY DECREASINGSINCE YESTERDAY...AND DEVELOPMENT...IF ANY...WILL BE SLOW TO OCCUR. THIS SYSTEM HAS A LOW CHANCE...10 PERCENT...OF BECOMING A TROPICALCYCLONE DURING THE NEXT 48 HOURS AS IT MOVES SLOWLY TOWARD THEWEST-NORTHWEST.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THENEXT 48 HOURS.

LATE IN THE PERIOD... IT JUST WOULDN`T BE RIGHT IF MY LAST SHIFTAT WFO MIAMI/SOUTH FLORIDA DIDN`T HAVE A POTENTIAL TROPICALCYCLONE LURKING IN THE EXTENDED. THE GFS DEPICTS A TROPICALCYCLONE SPINNING UP FROM WHAT IS NOW THE DISTURBANCE NORTH OFPANAMA AND SLOWLY LIFTING NORTH AND INTERACTING WITH A STRONG COLDFRONT AS IT PASSES NEAR THE AREA. THE 0Z ECMWF NOW KEEPS THE TC INTHE CARIBBEAN AND POSSIBLY INTERACTING OR BEING ABSORBED BYANOTHER SYSTEM MOVING IN FROM THE EAST. THE BOTTOM LINE IS THATTHERE MAY BE A SYSTEM DEVELOPING IN THE WEST CARIBBEAN OVER THENEXT FEW DAYS, BUT UNCERTAINTY IS HIGH REGARDING THE EVOLUTION OFTHE TC.

That big upper level low to the north caused the weakening of 97L to the point that there is almost anything left. Yesterday morning,it looked very omminous down there with those black areas,but the tropics change constantly and here we are.

True!I was anticipating a rained-out weekend.Not looking that way, right now.

Hi- A bit gusty here on North Sound, but seems to have dropped from last night somewhat. Looks like we might get a bit of a break from the rain for a short while anyway. I see the 00 Nogaps puts 96L into Honduras/ Belize next week, but develops what appears to be influence from 97L over us & Jam' after mid-week

Quoting stormwatcherCI:Good morning Pottery. 97L looks to have consolidated pretty good over night but is a very small area. NHC latest surface map does not show a low there any longer though so I don't know what is going on with it.

Yeah, it seems less of a rain-threat now.Winds here were West and NW yesterday afternoon, which was interesting.

Quoting pottery:Good Morning.Pretty dawn this morning, which surprised me. I was expecting cloudy sky and the chance of rain from 97L.Looks like everything might move North of us.Still expect to get some showers, but not as much as it looked like, last night.

Good morning pottery.

That big upper level low to the north caused the weakening of 97L to the point that there is almost anything left. Yesterday morning,it looked very omminous down there with those black areas,but the tropics change constantly and here we are.

Quoting pottery:Good Morning.Pretty dawn this morning, which surprised me. I was expecting cloudy sky and the chance of rain from 97L.Looks like everything might move North of us.Still expect to get some showers, but not as much as it looked like, last night.

Good morning Pottery. 97L looks to have consolidated pretty good over night but is a very small area. NHC latest surface map does not show a low there any longer though so I don't know what is going on with it.

Good Morning.Pretty dawn this morning, which surprised me. I was expecting cloudy sky and the chance of rain from 97L.Looks like everything might move North of us.Still expect to get some showers, but not as much as it looked like, last night.

Ok,now what? The 00z Euro almost doesn't show it and 06Z GFS drops it.

Most likely because it hasn't developed as quickly as they originally thought it would. I put a lot of stock in kmanislander and when he says we most likely will get development from this I think we will. He has never that I can remember been wrong and definitely does not hype any system.

Quoting TropicTraveler:Good morning island people. You are up way to early for a Saturday morning, but then, nothing like a sunrise over the water to start the day right. I'm mad cause I started to work and forgot my coffee!!! Grr. Late yesterday our resident grump was complaining that we all get excited when a storm cranks up. After I logged off I laughed because of course we get excited when a storm cranks up. This is a tropical weather blog and we are tropical weather junkies so that's what we do.......I'd say it beats being crabby and picking on us weather nuts for being who we are. Wonder why the guy even logs on here. Just saying.

Good morning. I am normally an early riser and I think we definitely need to watch 96L in the Cayman Islands. The blog has gone to the dogs over the past few weeks but I just ignore the trolls. It serves no purpose arguing with them since that is their whole purpose for coming on here.

Good morning island people. You are up way to early for a Saturday morning, but then, nothing like a sunrise over the water to start the day right. I'm mad cause I started to work and forgot my coffee!!! Grr. Late yesterday our resident grump was complaining that we all get excited when a storm cranks up. After I logged off I laughed because of course we get excited when a storm cranks up. This is a tropical weather blog and we are tropical weather junkies so that's what we do.......I'd say it beats being crabby and picking on us weather nuts for being who we are. Wonder why the guy even logs on here. Just saying.

AN AREA OF LOW PRESSURE...LOCATED OVER THE SOUTHWESTERN CARIBBEANSEA NEAR SAN ANDRES ISLAND...CONTINUES TO PRODUCE WIDESPREADCLOUDINESS AND THUNDERSTORMS. ALTHOUGH THERE HAS BEEN LITTLE CHANGEIN THE ORGANIZATION OF THIS DISTURBANCE DURING THE PAST SEVERALHOURS...UPPER-LEVEL WINDS ARE FORECAST TO BE FAVORABLE FOR THEDEVELOPMENT OF A TROPICAL DEPRESSION DURING THE NEXT DAY OR TWO.THIS SYSTEM HAS A HIGH CHANCE...70 PERCENT...OF BECOMING A TROPICALCYCLONE DURING THE NEXT 48 HOURS AS IT DRIFTS SLOWLY NORTHWARD.SHOWERS AND THUNDERSTORMS REMAIN LIMITED IN ASSOCIATION WITH A BROADAREA OF LOW PRESSURE LOCATED SEVERAL HUNDRED MILES EAST OF THEWINDWARD ISLANDS. UPPER-LEVEL WINDS ARE EXPECTED TO BECOME MOREFAVORABLE DURING THE NEXT DAY OR TWO...AND SOME SLOW DEVELOPMENT OFTHIS DISTURBANCE IS POSSIBLE. THIS SYSTEM HAS A LOW CHANCE... 20PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURSAS IT MOVES SLOWLY WEST-NORTHWESTWARD. REGARDLESS OF DEVELOPMENT...CLOUDINESS AND HEAVY RAINS COULD SPREAD OVER PORTIONS OF THEWINDWARD ISLANDS AND NORTHERN VENEZUELA DURING THE NEXT FEW DAYS.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THENEXT 48 HOURS.

Looks like that strong ULL north of PR is starting to slowly move north now. It has been responsible for strong northerly upper level winds on the east side of 96L, and tearing up 97L. It looks to me like things will begin to improve for 96L now in terms of organization, while 97L will still be under the ULLs influence.

Thanks, noticed updating my blog. I didn't get to read back more than a few pages. No mention. Probably about to get shredded anyways. Good to see we (as a group) aren't missing these the moment they come out.

Thanks, noticed updating my blog. I didn't get to read back more than a few pages. No mention. Probably about to get shredded anyways. Good to see we (as a group) aren't missing these the moment they come out.

Hadn't expected to post another mapping so soon, but since the previous mapping for 21Oct_6pmGMT :6pmGMT's D(istur)B(ance) has been re-evaluated&altered to (closed)LO(w) for Invest97L's_12amGMT_ATCF, and8.5n54.4w, 8.6n54.8w, 8.7n55.2w, 8.8n55.7w, 9.0n56.2w have been re-evaluated&altered to 9.4n53.4w, 9.5n53.9w, 9.7n54.5w, 10.0n55.0w, 10.6n55.7w, 11.4n56.3w being the most recent positionsStarting 20Oct_6pmGMT and ending 22Oct_12amGMT The 5 line-segments represent Invest97L's northwestward path

A flash flood in central Myanmar on Friday left dozens of people missing as homes along a river bank were swept away, government officials in the military-dominated country said. "About 60 people are missing so far because of the flood" in Pakokku township, an official who did not want to be named, said. "Some houses and a monastery along the river bank were swept away and a bridge was destroyed as the water rose up," he said. There were no confirmed reports of deaths, a second official said. A monk in Pakokku said the water was believed to have risen to about three metres (10 feet) high. "Some people, animals, houses and a monastery were swept away when the water rose up. The water level is back to normal now," he said. "We had torrential rain in previous days." State media reported roads, bridges and buildings were damaged because of strong winds and heavy rains in some parts of the country. Southeast Asia has been battered by particularly severe monsoon rains this year. According to the United Nations, more than 700 people have been killed across Thailand, Cambodia, Vietnam, Laos and the Philippines, and eight million have been affected. Thailand has been particularly severely hit, with more than 300 people dead and Bangkok on alert for flooding.

Tsunami has been observed following the M7.4 magnitude earthquake in Raoul Island, Kermadec Island, New Zealand at 18:16 Zulu. The observed tsunami waves 10 centimeters high. Other information not available yet.

Kinda odd almost 2 dueling ULL North of the Leeward Islands, wrapped in a layer of dry air. Should do the trick to disrupt the stationary front, completely cut off that low & give it a little tug north as it goes.